In some cases, it may be advantageous to perform computing operations using an actor-based model in which multiple actors execute on multiple hubs within a computing system, and individual actors receive and respond to various messages. In some examples, actors may sometimes be employed to perform operations associated with graphical objects in video games and other electronic media, operations associated with electronic mail, web services, and other operations. Also, in some cases, it may be advantageous to have a single instance of a given actor in the actor-based system, which is referred to hereinafter as a singleton actor. For example, it may sometimes be advantageous to have a singleton actor for cases in which it is simpler to implement an actor's associated functionality using a single actor than in a more distributed fashion. However, the coordination of singleton actors in an actor-based system may present a number of challenges. For example, basic realities of distributed systems (e.g., lost messages, network partitioning, etc.) will inevitably result in duplicate live actors. Additionally, actors and hubs may often be terminated, sometimes unexpectedly, therefore making it difficult to ensure that an instance of a particular singleton actor continues to execute in the system at any given time.